Relatives of miners killed or injured in the mine explosion react as rescuers work in Soma, a district in Turkey's western province of ManisaReuters

The ruling AK Party has come under a barrage of criticism in Turkey following the Soma coal mine explosion that has killed at least 205 people and left hundreds more trapped underground.

Prime Minister Recep Tayyip Erdogan's party has been accused of dismissing a parliamentary motion submitted by the opposition Republican People's Party (CHP) to investigate safety in the Soma mines as recently as 29 April.

The CHP local deputy for Manisa province, where Soma is located had denounced the frequent mine accidents and deaths that should have served as warning to avoid major disasters. But the parliament rejected the investigation with votes from the AK Party.

An AKP lawmaker from the same province even boasted that Turkish mines were safer than others, according to reports.

The hashtag #kazadegilcinayet which roughly translates as "murder not an accident" is trending on Twitter.

Protests are planned in front of the Istanbul headquarters of Soma Komur Isletmeleri, the operators of the mine. The head of the Confederation of Progressive Trade Unions (DISK), which is one of the major unions in Turkey, said that a large number of subcontracted workers were operating in the mine.

"There are second and third-tier subcontractors working in this mine. I hope that the death toll will not further climb, but I am not optimistic. There is a massacre that happened following the explosion inside," Kani Beko said.

Among the dead was a 15-year-old boy employed illegally at the mine.

Turkish energy minister Taner Yildiz has called the Soma fire "the country's deadliest accident ever" as 300 more workers are feared to be trapped inside. Most of the victims died due to carbon monoxide poisoning, according to officials.

"We are worried that this death toll will rise...I have to say that our hopes are dimming in terms of the rescue efforts," Yildiz said.

The explosion took place after 3pm on Tuesday and triggered a deadly inferno still burning underground, hindering rescue efforts.

Yildiz added that 787 workers had been in the mine at the time of the blast. A cold storage warehouse, usually used for food, and freezer trucks were transformed into makeshift morgues.

The government has ordered Turkish flags to fly at half-mast and a 3-day national mourning.

Ruling AKP deputy Şamil Tayyar described the opposition CHP's motion to set up investigation into coal mine accidents as "quibbling"